pump will rupture any crystalline structure that
may have formed, if the oil is not actually con-
gealed, thereby restoring fluidity. But oil is
usually supplied to the pump by gravity, and it
can not be expected to reach the pump under
these conditions, if the temperature is below the
pour point. Passenger car engines and many
machines that are stopped and started under
low-temperature conditions require an a oil that
will flow readily when cold.
may have formed, if the oil is not actually con-
gealed, thereby restoring fluidity. But oil is
usually supplied to the pump by gravity, and it
can not be expected to reach the pump under
these conditions, if the temperature is below the
pour point. Passenger car engines and many
machines that are stopped and started under
low-temperature conditions require an a oil that
will flow readily when cold.
What is true of circulating lubrication systems,
moreover, is equally true of gravity-feed oilers
and hydraulic systems. A low-pour-point oil
helps to provide full lubrication when the equip-
ment Is started and is easier to handle in cold
weather. Low pour Point is especially desirable
in a transformer oil, which must circulate under
all temperature conditions. The control of large
moreover, is equally true of gravity-feed oilers
and hydraulic systems. A low-pour-point oil
helps to provide full lubrication when the equip-
ment Is started and is easier to handle in cold
weather. Low pour Point is especially desirable
in a transformer oil, which must circulate under
all temperature conditions. The control of large
aircraft is dependent upon hydraulic oils that
must remain fluid after being exposed to ex-
treme temperature drops. For these and similar
applications, pour point is a very Important con-
sideration.
must remain fluid after being exposed to ex-
treme temperature drops. For these and similar
applications, pour point is a very Important con-
sideration.
If the temperature of an oil does not drop below
its pour point, the oil can be expected to flow
without difficulty. It sometimes happens, how-
ever, that oil is stored for long periods at
temperatures below the pour point. In some
cases, the waxy crystalline structure that may be
formed under these circumstances will not melt
and redissolve when the temperature of the oil
is raised back to the pour point. To pour the oil
under these conditions, it is necessary to put the
waxy crystals back In solution by heating the oil
well above its pour point.
its pour point, the oil can be expected to flow
without difficulty. It sometimes happens, how-
ever, that oil is stored for long periods at
temperatures below the pour point. In some
cases, the waxy crystalline structure that may be
formed under these circumstances will not melt
and redissolve when the temperature of the oil
is raised back to the pour point. To pour the oil
under these conditions, it is necessary to put the
waxy crystals back In solution by heating the oil
well above its pour point.
RUST-PREVENTIVE CHARACTERISTICS
ASTM D 665
This test method was originally designed to
indicate the ability of steam turbine oils to pre-
vent the rusting of ferrous parts should water
become mixed with the oil. While still used for
this purpose, its application is now often ex-
tended to serve as an indication of rust
preventive properties of other types of oils, par-
ticularly those used in circulating systems. It is
a dynamic test, designed to simulate most of the
conditions of actual operation.
indicate the ability of steam turbine oils to pre-
vent the rusting of ferrous parts should water
become mixed with the oil. While still used for
this purpose, its application is now often ex-
tended to serve as an indication of rust
preventive properties of other types of oils, par-
ticularly those used in circulating systems. It is
a dynamic test, designed to simulate most of the
conditions of actual operation.
In the method, a standard steel specimen is
immersed in a mixture of the test oil and water
under standard conditions and with constant
stirring. At the end of a specified period, the
steel specimen is examined for rust. Depending
on the appearance of the specimen, the oil is
rated as passing or failing.
immersed in a mixture of the test oil and water
under standard conditions and with constant
stirring. At the end of a specified period, the
steel specimen is examined for rust. Depending
on the appearance of the specimen, the oil is
rated as passing or failing.
Apparatus and Materials: The apparatus re-
quired consists of a constant-temperature oil
quired consists of a constant-temperature oil
bath with cover, a 400-ml beaker with cover,
grinding and polishing equipment, a stirrer, and
a thermometer.
grinding and polishing equipment, a stirrer, and
a thermometer.
Water used for the test may be either distilled
water (Procedure A of D 665) or synthetic sea
water (Procedure B), depending on the informa-
tion required of the test. Synthetic sea water is
prepared according to a formula given In the
ASTM method. The specimen used in the test is
a cylinder of 1015, 1020, or 1025 carbon steel
approximately 2.7 inches long and 0.50 inches
in diameter. The specimens can be used more
than once; they are prepared for each test by a
grinding and polishing operation. Specimens are
discarded when the diameter is reduced to 0.375
inch.
water (Procedure A of D 665) or synthetic sea
water (Procedure B), depending on the informa-
tion required of the test. Synthetic sea water is
prepared according to a formula given In the
ASTM method. The specimen used in the test is
a cylinder of 1015, 1020, or 1025 carbon steel
approximately 2.7 inches long and 0.50 inches
in diameter. The specimens can be used more
than once; they are prepared for each test by a
grinding and polishing operation. Specimens are
discarded when the diameter is reduced to 0.375
inch.
Procedure: The steel specimen is first prepared
by grinding and polishing to remove surface
blemishes. The 400-ml beaker is then
by grinding and polishing to remove surface
blemishes. The 400-ml beaker is then
A-15 (FIST 2-4 11/90)